Photonic devices are used in many applications including medicine, manufacturing, telecommunications, data storage, computing, and imaging. Nonlinear photonic devices have the potential to provide processing that is primarily performed electronically.
Most modern nonlinear devices achieve high efficiency through quasi-phase matching (QPM), which enhances nonlinear interactions by periodically alternating the direction of the material's polarization. This polarization engineering is performed during device fabrication, and is permanently frozen in to the device. However, a QPM photonic device can only perform the nonlinear operations that are hard-wired into the device during fabrication, limiting its versatility. The permanent nature of QPM is a limitation for reconfigurable photonic and hybrid photonic/electronic circuits. Each desired nonlinear interaction for every operation that a photonic or hybrid photonic/electronic circuit might run must have (quasi-) phase-matched nonlinear devices in the circuit. Furthermore, attempts to make a device more versatile by broadening the phase matching bandwidth of a single nonlinear element inherently results in lower nonlinear conversion efficiency. Ferroelectric materials like lithium niobate can have their quasi-phase matching grating erased and re-written via electric field poling, but the process requires 1) defining a new QPM pattern on the device, typically through multiple rounds of photolithography, and 2) applying an electric field in excess of 20 kV/mm for typical device configurations. This process is only possible in a laboratory setting, and even then, roughly 1 in 5 attempts at electric field poling destroy the device due to dielectric breakdown.
What is needed is a device and method for in situ reconfigurable quasi-phase matching field-programmable nonlinear photonics that is reliably reconfigurable and maintains nonlinear conversion efficiency.